class_docstr: Detection dataset wrapper that performs mixup for normal dataset.
  
  Parameters
  ----------
  dataset : mx.gluon.data.Dataset
      Gluon dataset object.
  mixup : callable random generator, e.g. np.random.uniform
      A random mixup ratio sampler, preferably a random generator from numpy.random
      A random float will be sampled each time with mixup(*args).
      Use None to disable.
  *args : list
      Additional arguments for mixup random sampler.
code: def __len__(self):
      return len(self._dataset)
  
file_path: gluon-cv/gluoncv/data/mixup/detection.py
imports: from __future__ import absolute_import
  import numpy
  import mxnet
  from mxnet.gluon.data import Dataset
label_desc: Use image node_id 3 for calling the MixupDetection obj's underlying member method code with example usage: obj.__len__() and returns: len